Functional polyester blending system and method based on direct melt injection

Abstract

The invention provides a functional polyester blending system and method based on melt direct injection. The system comprises a double-screw extruder, a melt feeding port, a side feeding port and a granulator. Wherein the extruder barrel is divided into a plurality of temperature control sections in the material conveying direction, the melt feeding port is located in the second section and used for directly receiving PET melt from a polymerization device, and the side feeding port is located in the fourth section and used for injecting toner and auxiliaries. The method comprises the following steps: directly injecting PET melt generated by polymerization of PTA and ethylene glycol into an extruder; adding toner and auxiliaries through side feeding; and after melting and mixing in an extruder, extruding and pelletizing. According to the invention, the crushing and premixing processes of the traditional process are omitted, and the method has the advantages of low pollution, high productivity, low energy consumption, simple process and stable product quality.

Description

Technical Field

[0001] This invention relates to the field of polymer material processing technology, and in particular to a functional polyester blending system and method based on melt direct injection. Background Technology

[0002] Polyethylene terephthalate (PET), as an important engineering plastic, is widely used in packaging, fiber, and electronics due to its excellent mechanical properties, chemical resistance, and recyclability. In practical applications, it is often necessary to add color powders, additives, etc. to the PET matrix through blending modification to prepare functional polyester materials with specific colors or functions.

[0003] Currently, the conventional functional polyester blending granulation production process in the industry usually includes the following steps: First, solid PET granules or bottle flakes are crushed by a pulverizer to obtain PET powder; then, the PET powder, color powder, and various additives are put into a high-speed mixer for premixing and dispersion to obtain a uniform powder mixture; finally, this powder mixture is fed into a twin-screw extruder for melt blending, extrusion through the die head, water cooling, and pelletizing to finally obtain product particles.

[0004] However, this traditional process has many inherent technical defects, which seriously restrict the improvement of product quality and production efficiency. First, the raw materials need to undergo a secondary processing of melting and solidification. This repeated thermal history will cause the intrinsic viscosity of the final product to be significantly reduced compared with the initial raw materials. Second, the crushing and high-speed stirring processes will generate a large amount of material dust, as well as color powder and additive dust, which can easily cause pollution and waste of raw materials. In addition, the entire process is lengthy, complicated, and has high production costs and low production efficiency.

[0005] Therefore, there is an urgent need in this field for a novel blending method and system that can overcome the above-mentioned defects, in order to stably produce high-quality functional polyester composite materials while simplifying the process and reducing energy consumption and costs. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a functional polyester blending system and method based on melt injection, which has the advantages of low pollution, high production capacity, low energy consumption, simple process, and stable product quality.

[0007] The above-mentioned technical objective of the present invention is achieved through the following technical solution: A functional polyester blending system based on melt injection, comprising: An extruder has its barrel divided into several sections along the material conveying direction, including a melt feeding section, a feeding section, at least one blending section, and an extrusion section; A melt inlet is used to inject raw material melt into the melt inlet section; A side feed port is located at the barrel corresponding to the blending section, used to inject color powder and additives into the extruder; A pelletizer, located at the end of the extruder, is used to pelletize the final product particles.

[0008] Furthermore, the melt inlet is located in the first or second section along the material conveying direction, which is the melt inlet section.

[0009] Furthermore, the section where the side feed port is located is the feeding section, which is downstream of the melt feed section and is separated from the melt feed section by at least one section.

[0010] Furthermore, the extrusion section is the last section on the barrel along the material conveying direction.

[0011] Furthermore, the barrel of the extruder is divided into eleven sections, with the melt inlet located in the second section and the side feed inlet located in the fourth section.

[0012] This invention also provides a method for blending functional polyesters based on melt injection, comprising the following steps: S1, the raw material melt is directly injected into the melt feed section of the extruder; S2, the color powder and additives are side-fed through the extruder and injected into the barrel of the extruder in the feeding section downstream of the melt feeding section; S3, the raw material melt is melt-blended with the color powder and additives in an extruder to form a uniform blended melt; S4, the blended melt is extruded, cooled and pelletized to obtain functional polyester composite particles.

[0013] Furthermore, the color powder includes, but is not limited to, black powder or white powder.

[0014] This invention offers the following advantages: By directly injecting polyester melt into the extruder, the step of pulverizing solid raw materials is fundamentally avoided, completely eliminating dust pollution and raw material waste during the production process, thus achieving clean production. More importantly, this method eliminates the process of remelting materials from powder, significantly reducing the thermal history and thermal degradation of polyester materials, effectively preserving the intrinsic viscosity of the final product, and significantly improving the mechanical properties of the product. At the same time, utilizing the excellent dispersion ability in the melt environment ensures the uniform distribution of additives in the matrix, improving the consistency of product appearance and performance. The entire process is greatly simplified, reducing equipment investment, while lowering overall energy consumption and production costs, achieving high-quality, high-efficiency, and low-consumption green manufacturing. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the process flow of the present invention; Figure 2 This is a schematic diagram of the extruder section according to an embodiment of the present invention. Detailed Implementation

[0016] The technical solutions of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0017] A functional polyester blending system based on melt injection includes an extruder and a pelletizer, with a melt inlet and a side feed inlet on the extruder.

[0018] The extruder is a co-rotating twin-screw extruder with a segmented barrel design, divided into eleven sections along the material conveying direction. In this embodiment, the first section is set as an idle zone with a temperature set at 275±2℃; the second section is set as a melt feeding section with a melt inlet and a temperature set at 280±2℃; the third section is set as an idle transition zone to establish a stable melt conveying environment with a temperature set at 278±2℃; the fourth section is set as a feeding section with a side feed inlet and a temperature set at 275±2℃; the fifth to tenth sections are set as blending sections with a temperature gradient gradually decreasing from 272℃ to 268℃; and the eleventh section is set as an extrusion section with a temperature set at 265±2℃.

[0019] The melt feed inlet is directly connected to the upstream PET polymerization unit via a high-temperature insulated pipeline. The PET polymerization unit is a conventional reactor, which will not be described in detail here. PET melt refers to the uncured, fluid polyester melt produced by esterification, polycondensation, and other polymerization reactions of purified terephthalic acid (PTA), ethylene glycol (EG), and other additives or catalysts, maintained at a temperature of 280±5℃. The high-temperature insulated pipeline for melt transportation is electrically heated throughout, maintaining a temperature of 280±2℃ to ensure that the melt does not solidify or degrade during transportation.

[0020] The side feed port is located in the fourth section, and the color powder and additives are stably and continuously fed into the extruder barrel through the side feed port.

[0021] The pelletizer is an underwater strip pelletizer, comprising a cooling water tank, a dryer, and a pelletizing head. The cooling water tank is equipped with a temperature control system, maintaining the water temperature at 18±2℃ to ensure sufficient cooling and solidification of the pellets. The configuration of the pelletizer is existing technology and will not be described in detail here.

[0022] Specific production process flow: Taking the production of black, glossy modified PET as an example, the process includes the following steps: Step S1: The raw material melt is transported through an insulated pipe at a stable flow rate of 20 tons / day to the melt inlet of the second section of the twin-screw extruder. The intrinsic viscosity of the melt is 0.68 dL / g, and the temperature is 280±5℃. Step S2: After the raw material melt, i.e., the PET melt, is stably injected into the extruder barrel, side feeding begins, and the color powder and additives are fed into the extruder through a loss-in-weight scale. Carbon black powder: addition amount 2.0 wt%, i.e. 16.66 kg / h; Composite additives: Addition amount is 0.5 wt%, i.e. 4.17 kg / h. Composite additives include antioxidants, lubricants, and dispersants, and the ratio can be adjusted according to the performance requirements of the final product.

[0023] Step S3: After the raw material melt, color powder and additives are combined in the fourth section, they are melt-blended to form a uniform blend melt.

[0024] Step S4: The fully homogenized blend melt is extruded through a die, with the die temperature controlled at 265±2℃. After being cooled in a cooling water tank, the extruded strip is cut into uniformly sized particles by a pelletizer. The cooling water temperature is controlled at 18±2℃ to ensure that the strip is fully solidified but not over-crystallized, ultimately yielding functional polyester composite particles. The final product is then placed in the finished product container.

[0025] Intrinsic viscosity test The functional polyester composite particles were tested according to GB / T 14190-2008 "Test Methods for Fiber Grade Polyester Chips (PET)": Test conditions: Phenol:tetrachloroethane = 1:1 was used as the solvent, and the test was conducted in a constant temperature water bath at 25±0.5℃.

[0026] Initial melt viscosity of raw material PET: 0.682 dL / g; Final product viscosity: 0.647 dL / g; Viscosity decrease: 5.1%.

[0027] This data is significantly better than the viscosity reduction of more than 20% achieved by traditional processes, proving that this method can effectively protect polymer molecular chains and avoid a significant decrease in the intrinsic viscosity of the final product compared to the initial raw materials.

[0028] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A melt direct injection based functional polyester blend system characterized in that, The application relates to a functional polyester composite particle and a preparation method thereof. The extruder comprises a barrel which is divided into a plurality of sections along a material conveying direction, including a melt feeding section, a feeding section, at least one blending section and an extruding section. A melt feeding port is arranged on the barrel of the extruder and is used for feeding raw material melt into the melt feeding section. A side feeding port is arranged on the barrel of the extruder and is used for feeding toner and additives into the extruder. A pelletizer is arranged at the end of the extruder and is used for cutting the extruded product into particles.

2. A melt direct injection based functional polyester blend system as claimed in claim 1, wherein, The melt feeding port is arranged in the first or second section along the material conveying direction, which is the melt feeding section.

3. A melt direct injection based functional polyester blend system as claimed in claim 2, wherein, The side feeding port is arranged in the feeding section, downstream of the melt feeding section and at least one section away from the melt feeding section.

4. A melt direct injection based functional polyester blend system as claimed in claim 3, wherein, The extruding section is the last section along the material conveying direction on the barrel.

5. A melt direct injection based functional polyester blend system as claimed in claim 4, wherein, The barrel of the extruder is divided into eleven sections, the melt feeding port is arranged in the second section and the side feeding port is arranged in the fourth section.

6. The melt direct injection based functional polyester blending process according to any one of claims 1 to 5, characterized in that, The application further discloses a preparation method of the functional polyester composite particle. S1, feeding raw material melt into the melt feeding section of the extruder; S2, feeding toner and additives into the barrel of the extruder through the side feeding port in the blending section downstream of the melt feeding section; S3, melt mixing the raw material melt, the toner and the additives in the extruder to form a uniform blending melt; S4, extruding, cooling and cutting the blending melt to obtain the functional polyester composite particle.

7. The functional polyester blending method based on melt direct injection according to claim 6, characterized in that, The toner includes but is not limited to black toner or white toner.

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